Allenic esters, process for preparation thereof and process for rearrangement thereof

Abstract

Allenic esters of the formula: ##EQU1## (specific examples of R, R 1 , R 2 , R 3 and R 4 are given) and a process for the preparation thereof which comprises reacting propargyl alcohol derivatives with 2-substituted ortho-acetic acid esters in the presence of an acidic catalyst. These allenic esters are rearranged in the presence of an alkali catalyst to form α, β, γ, δ-unsaturated carboxylic acid esters and are useful as intermediates in the synthesis of various perfumes, medicines, agricultural chemicals and the like.

What is claimed is: 
     
       1. A process for the preparation of allenic esters represented by the formula: ##EQU2## wherein R 1 , R 2  and R 4  each represents hydrogen or a radical having from 1-20 carbon atoms; R 3  represents a radical having at least 2 carbon atoms; R 2  and R 3  may together form a cyclic ring; and R represents a radical having from 1-8 carbon atoms, said process comprising reacting a propargyl alcohol derivative represented by the following formula: ##EQU3## wherein R 1 , R 2  and R 3  are as defined above with a 2-substituted ortho-acetic acid ester represented by the following formula: ##EQU4## wherein R 4  is as defined above and R 5 , R 6  and R 7 , which may be the same or different, have the same meaning as R defined above, in the presence of an acidic catalyst. 
     
     
       2. A process for the preparation of allenic esters of claim 1 wherein said radical of said R 1 , R 2  and R 4  has from 1-8 carbon atoms and wherein R 3  represents the group R'-A m  -, wherein R' represents a radical of 5-30 carbon atoms of the formula ##STR18## wherein n is an integer of 1-6, -A- is an alkylene, alkenyl or alkynylene radical having 1-3 carbon atoms, and m is an integer of 0-1, said process comprising reacting a propargyl alcohol derivative represented by the following formula: ##STR19## wherein R 1 , R 2  and R 3  are as defined above, with a 2-substituted ortho-acetic ester represented by the following formula:   R.sub.4 -- CH.sub.2 -- C(OR.sub.5).sub.3     wherein R 4  is as defined above and R 5  has the same meaning as R 1  in the presence of an acidic catalyst.   
     
     
       3. The process of claim 1 wherein the acidic catalyst is an acid selected from the group consisting of carboxylic acids, sulfonic acids, mineral acids and Lewis acids. 
     
     
       4. The process of claim 25 wherein the acidic catalyst is a fatty acid having from 3 to 6 carbon atoms. 
     
     
       5. The process of claim 1 wherein the reaction is carried out at a temperature of 50° to 200°C. 
     
     
       6. A process for continuously preparing an α, β, γ, δ-unsaturated carboxylic acid ester comprising adding an alkali catalyst to the reaction product mixture of a propargyl alcohol derivative selected from the group consisting of 3,7-dimethyl-1-octyn-6-en-3-ol, 3,7,11-trimethyl-3,10-dodecadien-1-yn-3-ol, and 3,7,11,15-tetramethyl-6,10,14-hexadecatrien-1-yn-3-ol with a 2-substituted ortho-acetic acid ester represented by the following formula: ##STR20## wherein R 4  is defined as in claim 1 and R 5 , R 6  and R 7 , which may be the same or different, have the same meaning as R in claim 1, without separating said allenic exter obtained therefrom and rearranging said allenic ester in the presence of said alkali catalysts to form said carboxylic acid ester. 
     
     
       7. The process of claim 6 wherein ester exchange is simultaneously conducted by conducting said rearrangement in the presence of an alcohol.